Telephone system.



H. G. WEBSTER.

' TELEPHONE SYSTEM. APPLIUATION FILED JULY 5, 190e.

921,318, Patented May 11, 1909.

k mi," QQ-"ll- B N L q 1 y D mf E HAL n Wdm i N, H 35mm/tvv Y jg Afm/ Masa-Eff UNITED STATES PATE lill @iiihlltllrl HARRY G. WEBSTER, OF CHICAGO, ILLINOIS, ASSIGNOR TO MILO C'. KELLOGG, OF CHICAGO, ILLIN OIS.

TELEPHONE SYSTEME.

Speccation of Letters Patent.

Patented May 11, 1909.

Application :tiled July 5, 1906. Serial No. 324,841.

To all whom fit may concern:

Be it known that I, HARRY Gr. lVnBsrna, residing in Chicago, county of Cook, and Stateot Illinois, have invented new and useitu] Improvements in Telephone Systems, of which the following is a specification..

lily invention relates to telephone eX- change systems and more particularly to the arrangement of 'the line circuits and associated apparatus by which the usual signals are transmitted and controlled by the subscriber and operator, and also to means for determining the busy or idle condition ol thc line.

T he principal object of the invention is to provide a novel organization of circuits and apparatus for accomplishing these functions, which shall be simple in construction, elimicient in operation and economical to manufacture.

ln carrying out my invention, I employ, in association with the telephone line circuit, a novel controlling relay of the so-called double-acting type. This double-acting relay, which is along the line of those disclosed by me in prior applications, is arranged to cause the display of a line signal in response to a partial euergization and to prevent such display when energized to a greater extent. This is preferably brought about by arranging the relay contacts so that they will be moved through a portion ot their maximum range in response to the partial energization ot the relay, and through their entire range in response to the greater energizationthe former to close the circuit of a signal'lamp, and the latter to interrupt said circuit. In addition to these functions, the relay also varies the connections to its windings, and the connection of the line limbs. In the cord circuit, I employ means for securing the greater energization of the relay during the application ot ringing current to the line limbs as well as during the establishment of connection. I also associate with the cord circuit a resistance or impedance which is included in circuit with a talking strand ot the cord during the operation-ot securing a busy test, but which is short eircuited normally and after the called subscriber has responded.

The nature and objects of the invention will more fully appear from the following detailed description, taken in connection with the accompanying drawing, and the scope of the invention will be particularly indicated .in the appended claims.

In the accompanying drawing, which illustrates diagrannnatically a telephone system constructed in accordance with a preferred torni of my invention, A and A indicate two substations which are connected to a central otlice by a suitable telephone line, and Il and I3 indicate two substations which similarly connected by another line. The equipment at the substations, which may be ot any preferred ty Je, is here shown as comprising a call-bell 7) in series with a condenser c connected from the lower contact ot' the switch-hook /z to ground. The switchhook 7L is connected to one limb of the line, and its upper or alternate contact is connected with the opposite limb of the line through the receiver 1 and transmitter 1f, these ii'istruments being included in bridge of the line when the switch-hook is raised.

At the central oliice, a relay 3 is provided for each line, having two windings, one ot' which is of low energizing capacity and is normally included in circuit with the battery C and the line limbs. rllhe other winding is of greater energizing capacity and is normally disconnected from the line limbs, but has its terminals carried to the springjacls or switchingl termina-ls by which connection established with the line for conversation. This relay is provided with an armattire-contact S adapted to be actuated when the relay energized by either or bot-h windings, and with other contacts 6, 9 and il adapted to be actuated only when the relay is energized to its greater extent. The winding T ot lower energizing capacity is 'preferably included in circuit with a battery C ot relatively low .foltage, whereas the winding e ot. greater energizing capacity is included in circuit with the battery I) or" relatively high voltage upon theestablislnnent of a connection. 1Vhen the subscriber A desires to initiate a call and removes his receiver trom its switch-hook, current will flow from the active terminal of battery C, through winding 7, the anvil contact ot armature 1l, thence to the substations through limbs 2 and 1 oit the line, and to the return or grounded side ot the battery C through armature 6 and its anvil contact. The battery C being of low voltage, and the Winding 7 of low energizing capacity, the relay will be only sutliciently energized to cause the actuation of armature contact 8. Upon such actuation, current Will How from the battery C, through lamp 5,V

armature 8 and armature 9 to the opposite side of the battery, causing the illumination of the lamp, Which indicates a calling signal to the operator.

Upon the insertion of the connecting plug P into a jack 10 of the calling line, current Will How from battery D, through Winding 20 of relay 16, strand 14 ot the cord circuit, the sleeve contacts of the plug P and. springjack 10, through Winding 4 of relay 3 and thence through the'tip contact pieces of the spring-j ack and plug, strand 12 of the cord circuit and Winding 22 of the supervisory relay 1G to the return side of the battery. The battery D being of relatively high voltage, and the Winding 4 of greater energizing capacity, the relay 3 is thus energized to its greatest extent, causing the actuation of all ot' its armature contacts. The actuation of contacts 6 and 11 disconnects the line limbs from their normal connections to Winding 7 and battery C and connects them to the tip and sleeve contact pieces respectively of the spring jacks 10, and current then llows from battery D, through the line limbs to the substation. It is to be understood that the Winding 4 of relay 3 is o't relatively high resistance and it Will be seen that the current, Which loivs through Windings 20 and 22 of supervisory relay 1Q, of relatively small value until the circuit is established through the substation. Upon the establishment of the circuit through the substation, relay 16, which is of the doubleacting type, is completely actuated and the supervisory lamp 1S is not illuminated. After the insertion of the plug, the operator actuates her listening-key 7c in the usual manner and learns What subscriber is desired, it being assumed in the present case that subscriber B or B is to be called. The operator tests in the usual manner by applying the tip of her calling plug O to the sleeve or testing contact of the spring-jack 10. These spring-jacks, as will be seen, are normally insulated from the line limbs and from the central battery and ground, and no current Will flow. It, however, a connection exist at some other spring-jack than the one tested, current vvill tloiv, When a busy test is made, over a path which may be traced as follows: from battery D, either through vinding 21, strand 15 and sleeve contact of plug O of the connected cord circuit or through Winding 20, strand 14 and sleeve contact of plug P; thence through the sleeve Contact oit` the tested jack, to the tip of the cord With which the test is being made, through strand 13, ringing keys g2 and g, through resistance Q8 and through Winding 22 ot relay 17 to the ret-urn side of the battery. The resistance 2S is sulliciently great to prevent an undue disturbance of the potential existing upon the terminal of the line tested if a conversation be in progress, and may be preferably in the form of impedance. After securing the busy test, the operator releases her listening key Which, by its upper or normally closed contact, completes a short circuit of resistance 28, thus preventing said resistance from interfering with the proper current tlotv to operate the supervisory relay 17.

rrssuming that the line be idle, the calling plug' O is inserted into the spark-jack 10 of the line desired; and in case the subscriber B be Wanted, ringing key g-g/ is actuated. The actuation ot this ringing key completes a circuit for relay 3, which may be traced trom battery D, through impedance z', contact Q9, key lever y, strand 13, Winding 4, strand 15 and key lever g to gremial` causing' the complete actuation of the relay contacts and thus connecting the tivo line limbs to the two terminals of the springjacks. At this time, a path for ruig-ing current is provided from generatorv Gr, through contact 30, key lever g, strand 13, armature G to limb 1 of the line and thence to ground through condenser c and bell Z) at the substation B. It is to be notedthat during the actuation of the ringing key g-g, the generator G is connected in multiple With battery D, but that this connection is broken as soon as the ringing key is released. It subscriber B be desired, ringing key g2-g3 is actuated, thus supplying battery to relay 3 from battery D through impedance 2' and strand 15 of the cord circuit and thence through Winding 4 and strand 13 to the ground or return side of the battery, thus energizing relay 3 to its fullest extent as before and establishing a circuit for generator G through Contact 32, key lever' g3 and strand 15 to limb 2 of the line and thence through the bell and condenser at substation B to ground. Upon the restoration of the ringing key, current from battery D Will tloiv through Winding 21 of relay 17, through strand 15, Winding 4 of relay strand 13 and Winding 22 of relay 17. Winding 4 being ot high resistance and of high energizing capacity. the armature contacts of relay 4 will be completely actuated; Whereas the current through windings 21 and 22 of relay 17 Will be only sutcient to cause the partial energization of relay 17, This partial energization is sufficient only to cause the actuation contact oi the connected jack to the sleeve l of armature contact 23, thus completing a llt,

circuit of battery l) through supervisory lamp 19, contact 23, contact Q5 and anvil 24 to the return side of the battery, causing the illumination ot the lamp. .At the same time, the actuation of contact-s 6 and 11 of relay 3 maintains the two limbs ot the line in connection with the two strands ot the cord circuit.

ilhen the subscriber answers, thus closing the circuit of the line limbs at the substation, an increased current will tlow through windings 21 and 2Q of relay 17, causing the complete actuation oil its contacts. This will interrupt the circuit of lamp 19 at contact and anvil Qi, causing its extinguishi'nent, and will cause the engagement of contacts 2G and 2T, thus establishing a short cirA cuit of resistance 28 separate from that controlled by the listening key 7c. rlhe srl scribers being now in conversation, an actua tion ct listening key will. not result in bringing resistance 28 into serial relation with the Strand 13, as when making a busy test, and consequently no interference with conversation will result.

lV hen either subscriber replaces his telephone, the current iriowing through his associated supervisory relay 16 or 17 is reduced to that value resulting from the connection existing through winding' 4 of relay 3, and the supervisory relay contacts then assume their intermediate or `partially actuated position, allowing the establishment ot a circuit through lamp 1S or 19, as previously indicated. The illumination ot both lampsl constitutes the usual signal for disconnection. it will be observed that the spring-jacks of the line and the winding Ll of relay 3, with which they are connecten, are normally disconnected from the line limbs and from the central battery and ground; and that when a connection is established and the relay 3 thus completely energized, its winding 4 is brought into bridge of the two line limbs. it will also be observed that the winding 7 ot low energizing capacity is associated with a battery C of relatively low voltage; whereas the battery D, by which the greater energization ot the relay is secured, is of high voltage, thus securing a very wide margin oit operation for the partial and complete actuation ot the relay contacts.

bviously in carrying out my invention, batteries D and C need not be separate batteries, but the connection shown to battery C may be made at an intermediate point of battery D, and it will also be understood that the various grounds indicated may be replaced by a common' return, and other alterations and modifications may be made without departing from the spirit and scope oitl my invention. I therefore do not wish to be limited to the speciiic matter illus trated, but aim to cover by the terms of the appended claims all such alterations and modilications.

That I claim as new and desire to secure by Letters Patent ot the United States is z- 1. A telephone system comprising a telephone line extending in two limbs from the substation to the central otlice, a two contact connection terminal therefor normally disconnected from the line limbs, a line signal, a controlling electromagnet, means under the control of the subscriber for energizing said magnet to cause the display ot said line signal, and means under the control ot the operator for energizing said magnet to cause the effacement ot' said signal and to cause the connection of the line limbs to said connection terminal contacts.

Q. Al telephone system comprising a telephone line extending in two limbs from a substation to a central office, a two contact connection terminal therefor normally disconnected from the line limbs, a line signal, a controlling electromagnet having a plurality ot energizing windings, means under the control of the subscriber for supplying current to one o1" said windings to energize said electromagnet, means responsive to such energization for displaying said signal, means under the control of the operator for supplying current to another otl said windings to cause a different energization ot said electromagnet, and means responsive to said dii'l'erent energization to efface said signal and to connect said line limbs to the contacts of said connection terminal.

A telephone system comprising a telephone line extending in two limbs from a substatioii to a central oflice, a two contact connection terminal therefor normally disconnected rom the line limbs, a line signal, a central source of current, a controlling electromagnet having a plurality of energizing windings, one included in a normally. open circuit with said source of current and said line limbs, and another included in circuit with the connection terminal contacts, means under the control of the subscriber Jfor closing said normally open circuit to energize said electromagnet, means Jfor displaying said signal in response to such energization, means under the control ot the operator tor supplying current to said other energizing winding to cause a different energization of said electromagnetl` and means responsive to said diiierent energization to efface said signal and to connect the connection terminal contacts to said line limbs.

al. A telephone system comprising a telephone line extending in two limbs from a substation to a central otlice, a two contact connection terminal therefor normally disconnected from the line limbs, a line signal, a controlling electromagnet, means under the control of the subscriber for supplying current of low potential to energize said magnet, means responsive to such energization for displaying said signal, means under the control of the operator for supplying' current of relatively high potential to energize said magnet to a greater extent, and means responsive to such greater energizat-ion for ett'acing said signal and connecting the line limbs to said connection terminal contacts,

5. A telephone system comprising a telephone line extending in two limbs from a substation to a central office, a two contact connection terminal therefor normally disconnected from the line limbs, a line signal, a controlling electromagnet having a plurality of energizing windings, means under the control of the subscriber for sijipplying current of low potential to one of said windings vto energize said electromagnet, means responsive to suoli energizat-ion to display said signal, means under the control of the operator for supplying current of relatively high potential to another of said windings to cause a different energization of said magnet, and means responsive to said different energization to effect said signal and to connect said line limbs to said connection terminal contacts.

G. telephone system comprising a tele- `phone line extending in two limbs from a substation to a central otiice, a two contact connection terminal therefor normally disconnected from the line limbs, a line signal, a controlling electro-magnet having a plurality of energizing windings, means under the control of the subscriber for supplying current of low potential to one of said windings to energize said electromagnet, means responsive to such energization to display said signal, means under the control of the operator for supplying current of relatively high potential to another of said windings to cause a greater euergization of said magnet, and means responsive to said dilerent energization to etfect said signal and to connect said line limbs to said connection terminal contacts.

7. A telephone system con'iprising a telephone line extending in two limbs from a substation to a central otlice, a two contact connection terminal therefor normally disconnected from the line limbs, a line signal, a relatively low potential source of current, a controlling electronnignet having a plurality of energizing windings, one included in a normally open circuit with said low potential current source and said line limbs and another included in circuit with the connection terminal contacts, means under the control of the subscriber for closing said normally pen circuit to energize said electromagnet, means for displaying said signal in response to such energization, means under the control of the operator for supplying current of relatively high potential to .said other energizing winding to cause a different energization of said electromagnet, and means responsive to said different energization to efface said signal and to connect the connection terminal contacts to said line limbs.

8. It telephone system comprising a telephone line extending in two limbs from a substation to a central otlice, a two contact connection terminal therefor normally disconnected trom the line limbs, a line signal, a relatively low potential source of current, a controlling' electromagnet having a plurality of energizing windings, one included in a normally open circuit with said low potential current source and said line limbs and another included in circuit with the connection terminal contacts, means under the control of the subscriber for closing said normally open circuit to energize said electromagnet, means for displaying said signal in response to such energization, a link-circuit and connecting plug for establishing connection with said connection terminal, a high potential source of current in bridge of the link-circuit strands whereby, upon the insertion oit' said plug into said terminal, said electromagnet will be energized through said other energizing winding, and means responsive to said latter energization for eftacing said signal and connecting said connect-ion terminal contacts to said line limbs.

Sl. It telephone exchange system comprising a telephone line extending in two limbs from a substation to the exchange, a signal, a relay for causing the display and effacement of said signal, means for causing the operation of said relay to display said signal. by closing a circuit over the limbs of said line in series, a source of ringing current, and one and the same means for temporarily applying ringing current to said line and causing the signal eitacing operation of said relay.

l0. A telephone exchange system comprising a telephone line connecting a substation with the exchange, a signal, a relay for controlling the display and elfacement of said signal, a spring-jack for said line normally disconnected therefrom, meansJ for causing the operation of said relay to display said signal by closing the circuit over said line, a source of ringing current, a ringingkey, means for connecting said ringing key to said jack, and means responsive to the operation of said ringing ltey for applying ringing current to the line and causing the signal etfacing operation of said relay.

li. A telephone exchange system comprising a telephone line ext-ending in two limbs from a substation to the exchange, a twocontact connection terminal therefor norwally disconnected from the line limbs, a ing the operation of said relay to eface said signal a relay for causing the display and signal. l0 el'iaeement of said signal, means under the In Witness whereof, I hereunto subscribe control of the subscriber for energizing said my name this 30th day of June 1906.

relay to cause the display of said signal, a HARRY G. WEBSTER. source of ringing current, means under the 1Witnesses:

conn-el of the operator for temporarily ap- Gno. E. MUELLER,

plying ringing current to said line and caus- A. H. DYSON.

It is hereby eertied that in Letters Patent No. 921,318, granted May 11,1909, upon the application of Harry G. Webster, of Chicago, Illinois, for an improvement in Telephone Systems, errors appear in the printed specification requiring correction, as follows: In line 83, page 2, the compound Word spark-jack should read sprengjack, and in lines 27 and 46, page 4, the word effect should read @face and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Ofce.

Signed and sealed this 22d day of June, A. D., 1909.

[SEAL] C. C. BILLINGS, Acting Commissioner of Patents.

Corrections in Letters Patent No. 921,318. 

